Recently sex attractants for a number of crop insect pests have been described in the literature. The active compounds are usually C.sub.10 to C.sub.16 acetates, alcohols or aldehydes, frequently with one or more double bonds being present (unsaturation). Some of these compounds have been tested only in laboratory tests with only one species present. Not all of these attractants are effective field attractants for one species only. Some compounds or mixtures will exhibit mild attractancy for several species but it is more important and useful to develop an attractant system which is specific for only one species. Even though artificial attractants have recently been found for several cutworm or armyworm species, it is impossible to predict what a species-specific field attractant for another species will be. Extensive trial-and-error testing in the field is required and the results cannot be predicted. Laboratory olfactometer or electroantennogram tests can serve as a preliminary screen but the results do not indicate the composition of a species-specific field attractant. Artificial field attractants discovered in this way do not necessarily coincide with the actual pheromone produced by the female moths.
The army cutworm, Euxoa auxiliaris (Grote), is a pest throughout the semiarid region of the Great Plains of the United States, in the Rocky Mountains and adjacent areas in the United States and Canada.
To our knowledge, nothing has been reported concerning an adult sex pheromone or an adult sex attractant for this species.
Light traps are the only present method of trapping the moths. The light trap attracts many species of moths that are flying at the same time as the army cutworm, and this makes it difficult or impossible to identify the pest species. The light traps are inefficient as only a few moths are captured when there are large numbers in the field. Light traps are expensive to purchase and operate, and they could never be used efficiently for monitoring the population density or for control of this pest.
The life cycle of the army cutworm has been reported and there is one generation per year (Crumb 1929, Walkden 1942, 1950). Blacklight trap records show that there is a flight of newly emerged moths about June and a second flight in August to October (Walkden 1942). Oviposition occurs during the second flight (Pruess 1967). The long interval between emergence and oviposition has been ascribed to a form of estivation (Seamans 1927). Pruess (1967) suggested, however, that the moths migrate to cooler mountainous areas during this period where they actually remain active. The exact time of mating under natural conditions has not been established.
It is desirable to have an adult male attractant that could be used to determine the population densities and habits of the moths and so predict larval infestations and outbreaks.